Synchronous temperature measurement method for diamond compact synthesis die

Abstract

The invention discloses a synchronous temperature measurement method for a diamond compact synthesis die, and the method comprises the steps: enabling the measurement ends of two thermocouple wires 1 to be respectively clamped on two opposite outer side walls of a graphite carbon tube, and enabling the other ends of the two thermocouple wires 1 to be led out from a gap between an upper pyrophyllite and a lower pyrophyllite, and then to be connected with an external temperature measurement module 1; measuring the external temperature of the graphite carbon tube in the pressing process of the composite sheet through a temperature measuring module I; and based on a synthetic die internal and external synchronous temperature measurement method, a temperature range value in a synthetic die synthesis cavity in the compact pressing process is obtained according to a temperature value measured by the temperature measurement module 1. According to the invention, on the basis of the measured external temperature of the graphite carbon tube and the internal and external temperature relationship of the synthetic die, the temperature distribution condition in the synthetic cavity of the synthetic die under the corresponding synthetic die assembly structure and pressing process conditions can be obtained, and a basis is provided for the structural design and pressing process optimization of the synthetic die; and the composite sheet is enabled to be synthesized in a proper temperature range.

Description

Technical Field

[0001] The present invention relates to the technical field of temperature measurement of a superhard material high-temperature and high-pressure synthesis chamber, and more specifically, to a synchronous temperature measurement method for a diamond composite sheet synthesis mold. Background Art

[0002] The synthesis mold consists of an outer layer of pyrophyllite pressure transmission medium, alloy plugs at both ends, metal gaskets, a central graphite carbon tube, a salt tube, a salt sheet and an internal synthesis cavity. Pyrophyllite has the properties of pressure transmission, sealing, insulation and heat preservation, so that the synthesis cavity inside the synthesis mold forms a stable high temperature and high pressure condition; at present, artificial diamond composite sheets are pressed and formed by diamond micropowder raw materials under high temperature and high pressure. The diamond composite sheet is located in the synthesis cavity of the synthesis mold, where the temperature is generated by the heating of the graphite carbon tube in the synthesis mold. The salt tube and salt sheet in the carbon tube can transfer the pressure evenly to the composite sheet after being heated and melted. The alloy plug and metal gasket have the functions of conducting electricity and transmitting pressure. The six-sided top press is controlled by a hydraulic system to push six carbide top hammers to evenly apply pressure to the synthesis mold from six directions to press the diamond composite sheet.

[0003] During the pressing process of the composite sheet, constant power or constant current is usually used to control heating. Different sintering processes or different structural designs of the composite mold have different heating temperatures. As the pressure and temperature increase, the size and resistivity of the heat-generating carbon tubes will also change, and the temperature of the composite sheet in the synthesis cavity will also change. In addition, each composite mold will also have inconsistent heating due to differences in assembly structure and parts. It is difficult to determine the actual temperature of the composite sheet diamond layer inside the synthesis cavity, and the temperature stability of the composite sheet product cannot be guaranteed. Therefore, it is very necessary to measure the temperature in the synthesis cavity of the composite mold after the structure of the composite mold changes or the pressing process is adjusted to ensure that the composite sheet is synthesized within the appropriate temperature range. Summary of the invention

[0004] Another object of the present invention is to provide a synchronous temperature measurement method for a diamond composite sheet synthesis mold, which provides a basis for the synthetic mold structure design and pressing process optimization based on the measured temperature of the outside of the graphite carbon tube and the temperature relationship between the inside and outside of the synthetic mold, ensuring that the subsequently pressed composite sheet is synthesized within a suitable temperature range.

[0005] In order to achieve these purposes and other advantages according to the present invention, a synchronous temperature measurement method for a diamond composite sheet synthesis mold is provided, including clamping the measuring ends of two thermocouple wires one on two opposite outer walls of the graphite carbon tube respectively, and the other ends of the two thermocouple wires one are led out through the gap between the upper and lower petals of talc and connected to an external temperature measurement module one, and the temperature of the outside of the graphite carbon tube during the pressing process of the composite sheet is measured by the temperature measurement module one; based on the synchronous temperature measurement method inside and outside the synthesis mold, the temperature range value in the synthesis cavity of the synthesis mold during the pressing process of the composite sheet is obtained according to the temperature value measured by the temperature measurement module one.

[0006] Preferably, based on the synchronous temperature measurement method inside and outside the synthetic mold, the temperature range value inside the synthetic cavity of the synthetic mold during the pressing process of the composite sheet is obtained according to the temperature value measured by the temperature measurement module 1, which specifically includes the following steps: S1. Using the overall positioning drilling method, a plurality of through holes are opened on the synthetic mold, wherein the plurality of through holes are distributed in the center and the edge of the two sides of the synthetic mold, and any through hole horizontally penetrates two opposite outer side walls of the synthetic mold, and any through hole is connected with the synthetic cavity of the synthetic mold; S2, making a plurality of temperature measuring wires, any one of which is formed by welding two identical thermocouple wires, respectively inserting the plurality of temperature measuring wires into a plurality of through holes, and adjusting the welding points of the temperature measuring wires to be located at corresponding temperature measuring points, avoiding the welding points, sleeved with a ceramic tube on the periphery of the temperature measuring wires, leading out the positive and negative electrodes of the plurality of temperature measuring wires through lead wires and correspondingly connecting with a plurality of external temperature measuring modules 2, and measuring the center temperature value and the edge temperature values ​​on both sides of the synthesis cavity of the synthesis mold during the pressing process of the composite sheet through the plurality of temperature measuring modules 2; S3. Calculate the difference between the measurement data of the temperature measuring module 1 and the temperature measuring modules 2 respectively, and based on the difference and the temperature value measured by the temperature measuring module 1, obtain the temperature range value in the synthesis cavity of the synthesis mold during the pressing process of the composite sheet.

[0007] Preferably, a magnesium oxide sheet is installed on the inner bottom surface of the synthesis chamber, a plurality of through holes are horizontally opened on the magnesium oxide sheet, the plurality of through holes are respectively connected to the plurality of through holes, and the welding points of the temperature measuring wire are located in the corresponding through holes.

[0008] Preferably, the positive electrode and the negative electrode of any temperature measuring wire are led out through the top hammer end face on the corresponding side through lead wires, and the top hammer end face is provided with a high temperature resistant insulating layer, and the thickness of the high temperature resistant insulating layer is 15-20 μm.

[0009] Preferably, the lead wire is copper foil; the thickness of the copper foil is 0.1-0.3 mm.

[0010] Preferably, the overall positioning drilling method includes: first using a clamping device to clamp the upper and lower end surfaces of the synthetic mold, and then positioning and opening the two opposite outer walls of the synthetic mold again according to the height positions of multiple temperature points to be measured; the opening direction of any through hole is perpendicular to the setting direction of the thermocouple wire.

[0011] Preferably, the distance between two adjacent temperature measuring wires is greater than 2 mm; the aperture of the ceramic tube is 1-1.5 mm; and the diameter of any thermocouple wire is less than 1 mm.

[0012] The present invention has at least the following beneficial effects: 1. Before batch pressing of diamond composite sheets, the present invention first simultaneously performs multi-point temperature measurement on different positions of the diamond layer in the synthesis cavity through multiple temperature measuring wires, thereby obtaining the temperature values ​​of each temperature-measured point in the synthesis cavity, and establishing the relationship between the temperature of the diamond layer in the synthesis cavity and the temperature outside the synthesis mold based on the difference between the temperature outside the graphite carbon tube and the temperature inside the synthesis mold; based on the measured temperature outside the graphite carbon tube and the temperature relationship between the inside and outside of the synthesis mold, the temperature distribution in the synthesis cavity of the synthesis mold under the corresponding synthesis film assembly structure and pressing process conditions can be obtained, providing a basis for the design of the synthesis mold structure or the optimization of the pressing process; 2. Based on the relationship between the temperature of the diamond layer in the synthesis cavity and the external temperature of the graphite carbon tube, in actual production, it is only necessary to assemble a simple external temperature measuring part of the synthesis mold to infer the actual temperature range of the composite sheet in the carbon tube, and optimize and adjust the synthesis temperature range according to the actual temperature range, so that the composite sheet can be synthesized within the appropriate temperature range to ensure the pressing quality of the composite sheet.

[0013] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a front cross-sectional view of the composite mold of the present invention; Figure 2 This is a schematic diagram of the assembly structure of the temperature measuring wire of the present invention; Figure 3 is a side cross-sectional view of the composite mold of the present invention; Figure 4 Schematic diagram of the assembly structure of the thermocouple wire of the present invention Description of the Figures in the Specification: 1. Alloy plug, 2. Metal gasket, 3. Pyrophyllite, 4. Graphite carbon tube, 5. Salt tube, 6. Salt sheet, 7. Synthetic chamber, 8. Magnesium oxide sheet, 9. Temperature measuring wire, 10. Temperature measuring point, 11. Ceramic tube, 12. Galvanic wire 1, 13. Top hammer. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings so that those skilled in the art can implement the invention with reference to the description.

[0016] It should be noted that, in the description of the present invention, the terms "lateral", "longitudinal", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside" and "outside" etc. indicating orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.

[0017] like Figure 1-4 As shown, the present invention provides a method for synchronous temperature measurement of a diamond composite sheet synthesis mold, such as Figure 3 , Figure 4 As shown, the measuring ends of two thermocouple wires 12 are respectively clamped on two opposite outer side walls of the graphite carbon tube 4, and the other ends of the two thermocouple wires 12 are led out through the gap between the upper and lower petals of talc 3 and connected to the external temperature measuring module 1, and the temperature of the outside of the graphite carbon tube 4 during the pressing process of the composite sheet is measured by the temperature measuring module 1; based on the synchronous temperature measurement method inside and outside the synthetic mold, the temperature range value in the synthetic cavity 7 of the synthetic mold during the pressing process of the composite sheet is obtained according to the temperature value measured by the temperature measuring module 1; Wherein, based on the synchronous temperature measurement method inside and outside the synthetic mold, the temperature range value inside the synthetic cavity 7 of the synthetic mold during the composite sheet pressing process is obtained according to the temperature value measured by the temperature measurement module 1, which specifically includes the following steps: S1. Using the overall positioning drilling method, a plurality of through holes are opened on the synthetic mold, and the plurality of through holes are distributed in the center and the edge parts of both sides of the synthetic mold. Any through hole horizontally penetrates two opposite outer side walls of the synthetic mold, and any through hole is connected with the synthetic cavity 7 of the synthetic mold; When drilling, first use the clamping device to clamp the upper and lower end surfaces of the synthetic mold, and then locate and open the two opposite outer side walls of the synthetic mold at once according to the height positions of the multiple temperature measurement points 10 to ensure the accuracy of each hole position; the opening direction of any through hole is perpendicular to the setting direction of the thermocouple wire 12, which can ensure that the layout positions of the thermocouple wire 12 and the multiple temperature measuring wires 9 do not interfere with each other, thereby ensuring the accuracy of the measurement data; S2, making a plurality of temperature measuring wires 9, any temperature measuring wire 9 is formed by welding two identical thermocouple wires, such as Figure 1 , Figure 2As shown, a plurality of temperature measuring wires 9 are respectively inserted into a plurality of through holes, and the welding points of the temperature measuring wires 9 are adjusted to be located at the corresponding temperature measuring points 10 to be measured, and the distance between two adjacent temperature measuring wires 9 is more than 2 mm, avoiding the welding points, and a ceramic tube 11 is sleeved on the periphery of the temperature measuring wire 9, and the temperature measuring wire 9 is isolated from the graphite carbon tube 4 by the ceramic tube 11, so as to avoid the temperature measuring wire 9 being connected to other circuits through the graphite carbon tube 4, resulting in measurement failure; the ceramic tube 11 can be an alumina ceramic tube, or a quartz tube, and the aperture of the ceramic tube 11 is 1-1.5 mm; the positive and negative electrodes of the plurality of temperature measuring wires 9 are led out through lead wires and respectively connected to the plurality of external temperature measuring modules 2, and the center temperature value and the edge temperature values ​​on both sides of the synthesis mold synthesis cavity 7 during the pressing process of the composite sheet are measured by the plurality of temperature measuring modules 2; S3. Calculate the difference between the measurement data of the temperature measuring module 1 and the temperature measuring modules 2 respectively, and based on the difference and the temperature value measured by the temperature measuring module 1, obtain the temperature range value in the synthesis cavity 7 of the synthesis mold during the pressing process of the composite sheet.

[0018] In the present technical scheme, before the batch pressing of diamond composite sheets, multiple temperature measuring wires 9 are used to simultaneously perform multi-point temperature measurement on different positions of the diamond layer in the synthesis cavity 7, so as to obtain the temperature values ​​of each temperature-measured point 10 in the synthesis cavity 7, and the relationship between the temperature of the diamond layer in the synthesis cavity 7 and the temperature of the outside of the graphite carbon tube is established based on the difference between the temperature outside the graphite carbon tube and the temperature inside the graphite carbon tube; based on the measured temperature outside the graphite carbon tube and the temperature relationship between the inside and outside of the synthesis mold, the temperature distribution in the synthesis cavity 7 of the synthesis mold under the corresponding synthesis film assembly structure and pressing process conditions can be obtained, which provides a basis for the design of the synthesis mold structure or the optimization of the pressing process; in actual production, only the assembly is required. The external temperature measuring parts of the synthesis mold with a simple structure can infer the actual temperature range of the composite sheet in the carbon tube, and optimize and adjust the synthesis temperature range according to the actual temperature range, so that the composite sheet can be synthesized within a suitable temperature range to ensure the pressing quality of the composite sheet; the temperature inside the synthesis cavity 7 is measured by opening a through hole to install the temperature measuring wire 9. The through hole is small in size and can be sealed by the top hammer 13 without damaging the edge sealing of the synthesis mold. Compared with other internal temperature measurement methods, it has better structural stability and higher measurement accuracy; when assembling the external temperature measuring parts, two thermocouple wires 12 are connected by the graphite carbon tube 4 to form a temperature measurement circuit, which is easy to assemble and does not damage the structure of the synthesis mold.

[0019] In another technical solution, a magnesium oxide sheet 8 is installed on the inner bottom surface of the synthesis chamber 7, and a plurality of through holes are horizontally opened on the magnesium oxide sheet 8. The plurality of through holes are respectively connected to the plurality of through holes, and the welding points of the temperature measuring wire 9 are located in the corresponding through holes.

[0020] In the present technical scheme, the magnesium oxide sheet 8 can, on the one hand, insulate the welding point of the temperature measuring wire 9, and on the other hand, ensure that the temperature measuring point 10 has good thermal conductivity, so that the measurement data is more accurate; the magnesium oxide sheet 8 is assembled before positioning drilling. During assembly, the alloy plug 1, metal gasket 2 and magnesium oxide sheet 8 at the bottom of the synthetic mold are first placed in the talc 3 of the lower lobe in order from bottom to top, and then the alloy plug 1, metal gasket 2, graphite carbon tube 4, salt tube 5 and salt sheet 6 at the upper end of the synthetic mold are assembled in the talc 3 of the upper lobe. After the assembly is completed, the upper and lower end faces of the synthetic mold are clamped by a clamping device, and drilling is performed again.

[0021] In another technical solution, the positive and negative electrodes of any temperature measuring wire 9 are led out through the end face of the top hammer 13 on the corresponding side through lead wires. The end face of the top hammer 13 is provided with a high-temperature resistant insulating layer, and the thickness of the high-temperature resistant insulating layer is 15~20μm; the lead wire is copper foil; the thickness of the copper foil is 0.1~0.3mm.

[0022] In the present technical solution, the lead wire adopts a more economical and more ductile copper foil, which can prevent the lead wire from being cut at the edge of the top hammer 13; the high-temperature resistant insulating layer is coated on the end face of the top hammer 13 to realize the conduction of the respective temperature measurement circuits, and avoid the mutual conduction of multiple temperature measurement circuits, so that data cannot be measured; the high-temperature resistant insulating layer is polytetrafluoroethylene, which is sprayed on the end face of the top hammer 13 by a spraying process.

[0023] Embodiment 1: Before batch pressing of a diamond composite sheet with a diameter of 16 mm, the synchronous temperature measurement method of the present invention is used to measure the temperature range value in a synthesis chamber 7 of a heating process section. Three temperature measuring wires 9 are provided, including a central temperature measuring wire 1, an edge temperature measuring wire 2 and an edge temperature measuring wire 3. The diameter of any temperature measuring wire is 0.9 mm, and the spacing between adjacent temperature measuring wires is 2 mm. The aperture of the selected ceramic tube is 1 mm, the spray thickness of the high-temperature resistant insulating layer is 15 μm, and the thickness of the copper foil used is 0.2 mm. The press used is a 650-specification six-sided top press produced by Guilin Metallurgical Plant, the maximum pressing power is set to 2900 W, and the system hydraulic pressure is 70 MPa; the synthesis temperature range of the heating process section designed for the diamond composite sheet is 1380~1400°C.

[0024] After the internal temperature measuring component and the external temperature measuring component are installed, the top press is started, and the temperature of the outside of the synthesis mold in the heating process section is measured to be 1570°C. At the same time, the temperature measured by the center temperature measuring wire 1 is 1350°C, and the temperatures measured by the edge temperature measuring wires 2 and 3 are both 1470°C, that is, the temperature outside the synthesis mold in the heating process section is 100~220°C higher than the temperature in the synthesis cavity 7; during batch pressing, only the carbon tube external temperature measuring circuit is assembled to monitor the temperature outside the synthesis mold. Based on the temperature relationship between the inside and outside of the synthesis mold, in order to ensure that the synthesis temperature of the composite sheet in the heating process section is between 1380~1400°C, the temperature outside the synthesis mold needs to be controlled to be maintained at 1500~1600°C, so as to ensure that the composite sheet has a good pressed morphology.

[0025] Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and implementation modes. They can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. A synchronous temperature measurement method for a diamond composite sheet synthesis mold, characterized in that: The method comprises clamping the measuring ends of two thermocouple wires 1 on two opposite outer walls of the graphite carbon tube respectively, and leading out the other ends of the two thermocouple wires 1 through the gap between the upper and lower petals of talc and connecting with an external temperature measuring module 1, and measuring the temperature outside the graphite carbon tube during the pressing process of the composite sheet through the temperature measuring module 1; based on the synchronous temperature measurement method inside and outside the synthetic mold, the temperature range value inside the synthetic cavity of the synthetic mold during the pressing process of the composite sheet is obtained according to the temperature value measured by the temperature measuring module 1.

2. The synchronous temperature measurement method of the diamond composite sheet synthesis mold according to claim 1, characterized in that: Based on the synchronous temperature measurement method inside and outside the synthetic mold, the temperature range value inside the synthetic cavity of the synthetic mold during the composite sheet pressing process is obtained according to the temperature value measured by the temperature measurement module 1, which specifically includes the following steps: S1. Using the overall positioning drilling method, a plurality of through holes are opened on the synthetic mold, wherein the plurality of through holes are distributed in the center and the edge of the two sides of the synthetic mold, and any through hole horizontally penetrates two opposite outer side walls of the synthetic mold, and any through hole is connected with the synthetic cavity of the synthetic mold; S2, making a plurality of temperature measuring wires, any one of which is formed by welding two identical thermocouple wires, respectively inserting the plurality of temperature measuring wires into a plurality of through holes, and adjusting the welding points of the temperature measuring wires to be located at corresponding temperature measuring points, avoiding the welding points, sleeved with a ceramic tube on the periphery of the temperature measuring wires, leading out the positive and negative electrodes of the plurality of temperature measuring wires through lead wires and correspondingly connecting with a plurality of external temperature measuring modules 2, and measuring the center temperature value and the edge temperature values ​​on both sides of the synthesis cavity of the synthesis mold during the pressing process of the composite sheet through the plurality of temperature measuring modules 2; S3. Calculate the difference between the measurement data of the temperature measuring module 1 and the temperature measuring modules 2 respectively, and based on the difference and the temperature value measured by the temperature measuring module 1, obtain the temperature range value in the synthesis cavity of the synthesis mold during the pressing process of the composite sheet.

3. The synchronous temperature measurement method of the diamond composite sheet synthesis mold according to claim 2, characterized in that: A magnesium oxide sheet is installed on the inner bottom surface of the synthesis cavity. A plurality of through holes are horizontally opened on the magnesium oxide sheet. The plurality of through holes are respectively connected with the plurality of through holes. The welding points of the temperature measuring wire are located in the corresponding through holes.

4. The synchronous temperature measurement method of the diamond composite sheet synthesis mold according to claim 2, characterized in that: The positive and negative electrodes of any temperature measuring wire are led out through the top hammer end face on the corresponding side through lead wires. The top hammer end face is provided with a high temperature resistant insulating layer, and the thickness of the high temperature resistant insulating layer is 15-20 μm.

5. The synchronous temperature measurement method of the diamond composite sheet synthesis mold according to claim 2, characterized in that: The lead wire is copper foil; the thickness of the copper foil is 0.1-0.3 mm.

6. The synchronous temperature measurement method for diamond composite sheet synthesis mold according to claim 2, characterized in that: The overall positioning drilling method includes: first using a clamping device to clamp the upper and lower end surfaces of the synthetic mold, and then positioning and opening the two opposite outer walls of the synthetic mold again according to the height positions of multiple temperature points to be measured; the opening direction of any through hole is perpendicular to the setting direction of the thermocouple wire.

7. The synchronous temperature measurement method of the diamond composite sheet synthesis mold according to claim 2, characterized in that: The distance between two adjacent temperature measuring wires is greater than 2 mm; the aperture of the ceramic tube is 1-1.5 mm; and the diameter of any thermocouple wire is less than 1 mm.

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